This invention relates to an oscillating apparatus utilizing an electro-rheological fluid for damping vibration of an object.
Vibration externally acting upon, for example, bodies, structures and like and disturbing them can be damped by applying controlled oscillation opposing to the vibration to the bodies and the like. Such control is referred to "active vibration control". The above apparatus is effective to produce oscillation for the active vibration control.
For active vibration control, hydraulic or pneumatic piston and cylinder assemblies have been used as oscillators (actuators). With the assemblies, oil or air is alternately supplied into and exhausted from cylinder chambers formed on both sides of a piston to produce vibrational movements of the piston. The vibrational movements are transmitted to the bodies and the like as control vibration. In such hitherto used oscillating apparatus, the supply and exhaust of the oil or air for the cylinder chambers are effected by mechanically rapidly closing and opening various kinds of servo-valves. Therefore, servo-valve mechanisms are complicated and frequently cause trouble. Moreover, performance of the apparatuses gradually declines with lapse of used time.
On the other hands, electro-rheological fluids have been known which are substantially solidified when applying electric voltage.